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64 lines
1.7 KiB
Python
64 lines
1.7 KiB
Python
"""Concept example of `Dependency Injector`."""
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import sqlite3
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import dependency_injector as di
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class UsersService(object):
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"""Users service, that has dependency on database."""
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def __init__(self, db):
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"""Initializer."""
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self.db = db
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class AuthService(object):
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"""Auth service, that has dependencies on users service and database."""
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def __init__(self, db, users_service):
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"""Initializer."""
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self.db = db
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self.users_service = users_service
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class Services(di.DeclarativeCatalog):
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"""Catalog of service providers."""
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database = di.Singleton(sqlite3.connect, ':memory:')
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""":type: di.Provider -> sqlite3.Connection"""
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users = di.Factory(UsersService,
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db=database)
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""":type: di.Provider -> UsersService"""
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auth = di.Factory(AuthService,
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db=database,
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users_service=users)
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""":type: di.Provider -> AuthService"""
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# Retrieving catalog providers:
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users_service = Services.users()
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auth_service = Services.auth()
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# Making some asserts:
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assert users_service.db is auth_service.db is Services.database()
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assert isinstance(auth_service.users_service, UsersService)
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assert users_service is not Services.users()
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assert auth_service is not Services.auth()
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# Making some "inline" injections:
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@di.inject(users_service=Services.users)
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@di.inject(auth_service=Services.auth)
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@di.inject(database=Services.database)
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def example(users_service, auth_service, database):
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"""Example callback."""
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assert users_service.db is auth_service.db
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assert auth_service.db is database
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assert database is Services.database()
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# Making a call of decorated callback:
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example()
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